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Fiber Optic Technology: Shining New Light On An Old Concept

While it may appear state-of-the-art on the surface, fiber optic technology is a fairly simple method of conducting light that has been around for some time. The principle of guiding light by refraction was first demonstrated in the mid 19th century, and has been developing for use in practical applications ever since.

Posted in: Articles, Features, ptb catchall, Photonics

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Method for Implementing Optical Phase Adjustment

A method has been developed to mechanically implement the optical phase shift by adjusting the polarization of the pump and probe beams in an NMOR (nonlinear magneto-optical rotation) magnetometer as the proper phase shift is necessary to induce self-oscillation. This innovation consists of mounting the pump beam on a ring that surrounds the atomic vapor sample. The propagation of the probe beam is perpendicular to that of the pump beam. The probe beam can be considered as defining the axis of a cylinder, while the pump beam is directed radially. The magnetic field to be measured defines a third vector, but it is also taken to lie along the cylinder axis. Both the pump and probe beams are polarized such that their electric field vectors are substantially perpendicular to the magnet field. By rotation of the ring supporting the pump beam, its direction can be varied relative to the plane defined by the probe electric field and the magnetic field to be measured.

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics

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Using Fan-poled Crystals to Tune Ti:S Lasers

Titanium:Sapphire (Ti:S)-based laser systems have revolutionized ultrafast research from biological imaging to high energy physics. Ti:S has a very broad gain bandwidth (680-1080 nm) but many applications require even broader tuning ranges covering UV, visible, and longer IR wavelengths. Frequency doubling, tripling, and quadrupling extend access to the 190-540 nm range. Ultrafast optical parametric oscillators (OPOs) pumped by Ti:S lasers reach beyond 1080 nm and fill in the “Ti:S gap” (540 to 680 nm).

Posted in: Articles, Features, ptb catchall, Photonics

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Using Optical Encoders to Improve Camera Phone Zoom Lens Accuracy

A wide range of commercial applications use cameras with a zooming mechanism. Perhaps the most ubiquitous is the camera phone. Camera phones may have an optical zoom, a digital zoom, or both. What’s the difference? An optical zoom actually changes the effective focal length of the camera lens such that the original image is magnified and could be captured by the image sensor (CCD or CMOS). With greater magnification, the light is spread across the entire image sensor and all of the pixels can be used. An optical zoom could be interpreted as a true zoom that will improve the quality of pictures captured.

Posted in: Application Briefs, Applications, ptb catchall, Photonics

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Wide-Field Optic for Autonomous Acquisition of Laser Link

This system has application in conventional wide-angle imaging such as low-light cockpit imaging, and in long-range motion detection. NASA’s Jet Propulsion Laboratory, Pasadena, California An innovation reported in “Two-Camera Acquisition and Tracking of a Flying Target,” NASA Tech Briefs, Vol. 32, No. 8 (August 2008), p. 20, used a commercial fish-eye lens and an electronic imaging camera for initially locating objects with subsequent handover to an actuated narrow-field camera. But this operated against a dark-sky background. An improved solution involves an optical design based on custom optical components for the wide-field optical system that directly addresses the key limitations in acquiring a laser signal from a moving source such as an aircraft or a spacecraft.

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics

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Method for Implementing Optical Phase Adjustment

Goddard Space Flight Center, Greenbelt, Maryland A method has been developed to mechanically implement the optical phase shift by adjusting the polarization of the pump and probe beams in an NMOR (nonlinear magneto-optical rotation) magnetometer as the proper phase shift is necessary to induce self-oscillation. This innovation consists of mounting the pump beam on a ring that surrounds the atomic vapor sample. The propagation of the probe beam is perpendicular to that of the pump beam. The probe beam can be considered as defining the axis of a cylinder, while the pump beam is directed radially. The magnetic field to be measured defines a third vector, but it is also taken to lie along the cylinder axis. Both the pump and probe beams are polarized such that their electric field vectors are substantially perpendicular to the magnet field. By rotation of the ring supporting the pump beam, its direction can be varied relative to the plane defined by the probe electric field and the magnetic field to be measured.

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics

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Multiple-Zone Diffractive Optic Element for Laser Ranging Applications

This technology can be used on unmanned aerial vehicles, or in collision-avoidance and robotic control applications in cars, trains, and ships. Goddard Space Flight Center, Greenbelt, Maryland A diffractive optic element (DOE) can be used as a beam splitter to generate multiple laser beams from a single input laser beam. This technology has been recently used in LRO’s Lunar Orbiter Laser Altimeter (LOLA) instrument to generate five laser beams that measure the lunar topography from a 50-km nominal mapping orbit (see figure). An extension of this approach is to use a multiple-zone DOE to allow a laser altimeter instrument to operate over a wider range of distances. In particular, a multiple-zone DOE could be used for applications that require both mapping and landing on a planetary body. In this case, the laser altimeter operating range would need to extend from several hundred kilometers down to a few meters.

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics

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